Ancient Greek

I don't know what it is other than utterly fantastic. I think that I have seen it before somewhere, but I can't put my finger on it. Is this supposedly authentic? Very beautiful either way.

Sadly, this is not an authentic coin - these are the reverses of two different coins. The facing owl in square punch with A Th E in the quarters is the reverse of the classic (and extremely valuable) dekadrachm of Athens - Wildwinds example - but the other side is some kind of quadripartite punch like that often used on the coins of other cities, such as Ephesus.

Sadly, no. Dekadrachms are all "uncommon varieties" to start with; a "double-tailed" mint error would have been extremely hard to create due to the fashion in which dies were made back then; reverse dies were in the form of a hand-held punch, while obverse dies were spikes driven into an anvil-like structure.

So a genuine coin like this surviving to the present day would be even less likely than finding a genuine double-headed 1933 Saint-Gaudens gold $20.

thanks a lot for all comments and replies...Actually I got it without paying several years ago.I have no idea if it is real or not.Perhaps it is really a very very rare thing which has never been discovered before.Who knows?Well,I will keep it anyway.thanks again.